Apparatus for holding and mounting a component

ABSTRACT

An electronic component mounting apparatus which employs a first air feed device connected to an air passage at one end part of a spline shaft, and a second air feed device connected to the air passage in the vicinity of the other end of the spline shaft. The first and second air feeds function to supply air to the air passage to return an interior thereof to atmospheric pressure. The time required to return the vacuum pressure in the air passage to atmospheric pressure can be shortened by the use of the two separate air feeds.

This application is a divisional of U.S. Ser. No. 09/921,982, filed Aug.6,2001, which is a divisional of U.S. Ser. No. 09/158,536, filed Sep.22, 1998, now U.S. Pat. No. 6,298,547.

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for holding components ofa type, e.g., mounting electronic components on electronic circuitboards, a component mounting apparatus with the component holdingapparatus and a component mount method carried out by the componentmounting apparatus.

A component sucking head part of a component mounting apparatus, whichautomatically mounts electronic components to an electronic circuitboard, has a nozzle for sucking the electronic components and therebymounting the component to the electronic circuit board. To preciselycontrol touching of the nozzle and the electronic component at the timeof the sucking and mounting is one factor in improving the quality ofthe electronic circuit board produced. An example of a conventionalelectronic component mounting apparatus will be described with referenceto FIG. 14.

FIG. 14 shows a component sucking head part 101 comprising the nozzle, asuction device 103 for sucking the electronic component by the nozzle,an X-Y robot 102 for moving the head part 101 in X, Y directions and acontrol device 104 for controlling operations of the head part 101. Thehead part 101 is constructed as described hereinbelow. FIG. 14 showsonly primary parts constituting the head part 101, and a body part ofthe head part 101, etc. are not illustrated in the drawing. A referencenumeral 135 in FIG. 14 denotes a spline shaft, having a nozzle 136 setat one end part 135 a for sucking an electronic component 138 through asuction operation and, a rotation receiver 143 provided at the other endpart 135 b.

The suction device 103 for carrying out the suction operation isconnected to the other end part of the spline shaft via a suction tube105. The air is sucked through the nozzle 136 and the spline shaft 135to the suction device 103 by the suction operation of the suction device103. A blow device 106 branches off the suction tube 105 and isconnected to the other end part 135 b of the spline shaft 135. The blowdevice 106 includes a valve for returning the interiors of the splineshaft 135 and nozzle 136 from a state in vacuum to a state ofatmospheric pressure so as to free the electronic component 138 from thesuction operation by the nozzle 136.

Two nuts 131, 134 are fitted to the spline shaft 135 to allow the splineshaft 135 to slide in the axial direction. These nuts 131, 134 are heldto the body part (not shown) of the head part 101 via respectivebearings 132, 133. The spline shaft 135 is accordingly movable in theaxial direction relative to the body part and also rotatable about anaxis of the spline shaft 135.

The rotation about the axis of the spline shaft 135 is conducted by amotor 142. A pulley 139 is engaged with the spline shaft 135, whichrotates along with the spline shaft 135. The spline shaft 135 is movablein the axial direction relative to the pulley 139. Meanwhile, a pulley141 is connected to a driving shaft of the motor 142. The pulley 139 andpulley 141 are coupled by a belt 140. When the pulley 141 is rotated bythe motor 142, the spline shaft 135 is rotated about the axis via thebelt 140 and pulley 139.

The movement in the axial direction of the spline shaft 135 is achievedby a motor 149. More specifically, a nut 146 projecting a lever 147 ismeshed with a ball screw 145 connected to a driving shaft of the motor149 via a coupling 148. The lever 147 has, at its leading end, a roller144 fitted in a groove 143 a formed in the rotation receiver 143.Therefore, when the ball screw 145 is rotated by the motor 149, thelever 147 moves in the axial direction with the roller 144 engaged withthe rotation receiver 143, thereby moving the spline shaft 135 in theaxial direction.

The operation of the conventional component mounting apparatus in theabove construction will be described with reference to FIG. 15.

At step (denoted by “S” in the drawing) 101, the X-Y robot 102 is movedby a control operation of the control device 104, thereby moving thehead part 101 to a component suction position where the electroniccomponent is to be sucked. At next step 102, the motor 149 is driventhrough the control of the control device 104 and, the spline shaft 135,namely, nozzle 136 is lowered. The suction device 103 is activated atstep 103, and as a consequence the electronic component is sucked by thenozzle 136 at step 104. At step 105, the ball screw 145 is turned inreverse-rotation by the motor 149 to move the nozzle 136 up. Thereafter,the motor 142 is driven by the control of the control device 104 torotate the nozzle 136 to a proper position so as to correctly positionthe sucked electronic component in a mount direction. At subsequent step106, the X-Y robot is operated again to move position on the motor 149is driven again to move the nozzle 136 down. Then at step 108 theelectronic component 138 is mounted on the electronic device 106 isdriven. After The mounting, the suction to the electronic component isreleased, at step 109, and then the nozzle 136 is raised via the splineshaft 135.

Recently, high-speed operation is required for the mounting of theelectronic component 138. However, in the above-described conventionalcomponent mounting apparatus, the blow device 106 is connected to theother end part 135 b opposite to the one end part 135 a of the splineshaft 135 where the nozzle 136 for sucking of the electronic component138 is arranged. Therefore, it takes a long time for the interior of thenozzle 136 to return to atmospheric pressure state after the blow device106 is activated to release the suction of the electronic component 138.In other words, the nozzle 136 stands still for a long time (a portionIV in FIG. 16) in a state while the electronic component 138 is mountedon the circuit board, thereby there is a disadvantage that the mountingtime (a portion V in FIG. 16) required for mounting the electroniccomponent 138 is increased. In the meantime, if the blow device 106 werestarted earlier during the descent of the nozzle 136 to shorten theabove mounting time, the nozzle 136 would be returned to the atmosphericpressure state before the electronic component 138 is completely mountedon the circuit board, thus causing the electronic component 138 to beblown away and mounted unstably.

SUMMARY OF THE INVENTION

The present invention was developed to solve the aforementioneddisadvantages and has for its object to provide an apparatus for holdingcomponents, an apparatus for mounting components which comprises thecomponent holding apparatus and a method for mounting components,whereby the mounting time for mounting components is shortened ascompared with the prior art.

In order to achieve the above-described object, according to a firstaspect of the present invention, there is provided an apparatus forholding a component which includes a shaft with a nozzle for holding ofthe component set at one end part thereof and moved in an axialdirection of the shaft.

The component holding apparatus comprising:

a suction device which is connected at the other end part of the shaftto an air passage formed in the shaft and communicating with the nozzleand which sucks an interior of the air passage, thereby letting thenozzle suck the component via the air passage and hold the component;

a first blow device which is connected at the other end part of theshaft to the air passage and which returns the interior of the airpassage to a state of an atmospheric pressure, thereby releasing thesuction of the component to the nozzle; and

a second blow device which is connected in the vicinity of the one endpart of the shaft to the air passage and which returns the interior ofthe air passage to the atmospheric pressure state, thereby releasing thesuction of the component to the nozzle.

An apparatus for mounting components according to a second aspect of thepresent invention has the component holding apparatus of the firstaspect.

The component mounting apparatus may be provided with a control deviceconnected to the first blow device and the second blow device, thecontrol device controlling an air feed start timing of the first blowdevice and the second blow device so that the air passage is turned tothe atmospheric pressure state in a period from a time of the nozzleholding the component and reaching a lowest fall point to a time of thenozzle starting to rise, thereby freeing the holding of the componentand then mounting the component on an object to which the component isto be mounted.

The feed start timing can be controlled on the basis of the weight ofthe component held by the nozzle.

In an apparatus for holding components in a third aspect of the presentinvention, there is provided an apparatus for holding a component, whichcomprises:

a shaft having a nozzle for holding of a component at one end part ofthe shaft and an air passage connecting the nozzle with an interior ofvoice coil motor, which is movable in an axial direction of the shaft inparallel to a groove formed in a circumferential face in the axialdirection thereof and rotatable in a direction about an axis of theshaft;

the voice coil motor formed like a can extending in the axial directionof the shaft, with having a casing in which the shaft penetrates acentral part in a state to be movable in the axial direction androtatable about the axis, wherein either one of a magnet and a coil isfixed to the circumferential face of the shaft and the other one of thecoil and the magnet is arranged inside the casing at the side of aperiphery of the shaft, thereby moving the shaft in the axial directionby an action of the magnet and the coil;

a suction device connected to the voice coil motor to suck the interiorof the voice coil motor and a interior of the air passage, therebyletting the nozzle suck and hold the component;

a first blow device connected via a suction tube to the voice coil motorand which returns the interiors of the voice coil motor and the airpassage to a state of an atmospheric pressure, thereby releasing thesuction of the component to the nozzle;

a second blow device connected to the voice coil motor and which returnsthe interiors of the voice coil motor and the air passage to theatmospheric pressure state faster than the first blow device, therebyreleasing the suction of the component to the nozzle; and

a sealing member with a first packing which is set at a part of thecasing of the voice coil motor where the shaft penetrates, formed in thesame sectional shape as the shaft, has a hole through which the shaftpenetrates, and prevents a leakage of air at the penetration part at asuction operation to the interior of the voice coil motor by the suctiondevice.

In a component holding apparatus according to a fourth aspect of thepresent invention, the sealing member may further comprise a pair ofsecond packings formed of a material of higher rigidity than that of thefirst packing, with holding the first packing therebetween, the secondpacking having a hole through which the shaft penetrates and aprojecting part in the periphery of the hole which is to be fitted inthe groove thereby rotating the second. packing in the same direction asthe direction about the axis of the shaft without accompanying arelative displacement to the shaft when the shaft rotates in thedirection about the axis.

In a component holding apparatus according to a fifth aspect of thepresent invention, the sealing member of the component holding apparatusaccording to the above fourth aspect may also be provided with an urgingmember interposed between the first packing and a packing at the side ofthe motor in touch with the casing of the voice coil motor among thesecond packings, which urges the packing at the motor side to the casingwith a pressing force breaking an air passage generated at a contactface part between the packing at the motor side and the casing when theinterior of the voice coil motor is returned to the atmospheric pressurestate by the first blow device and the second blow device, therebypreventing the leakage of air at the suction operation.

In an apparatus for mounting components in a sixth aspect of the presentinvention has the component holding apparatus of the third-fifthaspects.

The component mounting apparatus of the sixth aspect may include acontrol device connected to the first blow device and the second blowdevice, the control device controlling an air feed start timing of thefirst blow device and the second blow device so that the air passage isturned to the atmospheric pressure state in a period from a time of thenozzle holding the component and reaching a lowest fall point to a timeof the nozzle starting to rise, thereby freeing the holding of thecomponent and mounting the component on an object to which the componentis to be mounted.

The feed start timing may be a time point when the nozzle reaches thelowest fall point if a weight of the component held by the nozzleexceeds approximately 5 g.

In a method for mounting components according to a seventh aspect of thepresent invention, there is provided a method for mounting an electroniccomponent onto a circuit board by moving down a nozzle sucking theelectronic component to a lowest fall point in a thicknesswise directionof the electronic component, whereby an air feed start timing into thenozzle is set so that an interior of the nozzle is turned to a state ofatmospheric pressure in a period from a time of the nozzle reaching thelowest fall point to a time of the nozzle starting to rise in thethicknesswise direction, thereby releasing the suction and mounting theelectronic component onto the circuit board.

In the component mount method according to the seventh aspect, the airfeed into the nozzle may be terminated at a time point agreeing with atime point when the nozzle starts to rise.

Further, in the component mount method of the seventh aspect, the feedstart timing may be a time point when the nozzle reaches the lowest fallpoint if the weight of the electronic component held by the nozzleexceeds approximately 5 g.

According to the component holding apparatus of the first and thirdaspects of the present invention and the component mounting apparatus ofthe second and sixth aspects, because of the adoption of the aboveconstruction, the first blow device which is connected to the airpassage at the other end part of the shaft to return the interior of theair passage to the atmospheric pressure state, and the second blowdevice which is connected to the air passage in the vicinity of the oneend part of the shaft to return the interior of the air passage to theatmospheric pressure state are provided, so that a time required forreturning the vacuum pressure in the air passage to the atmosphericpressure can be shortened in comparison with the prior art.

According to the component holding apparatus of the third-fifth aspectsof the present invention, the presence of the sealing member preventsthe leakage of air at the part where the shaft penetrates the casing ofthe voice coil motor even when the component holding apparatus is of atype sucking the air passage through the interior of the voice coilmotor. Particularly the component holding apparatus of the fifth aspectis provided further with the urging member pressing the packing at theside of the motor to the casing of the voice coil motor. The leakage ofair at the penetration part by the shaft at the suction operation ishence more effectively prevented in the component holding apparatus of atype sucking the air passage through the interior of the voice coilmotor thereby returning to the atmospheric pressure state.

According to the component mount method of the seventh aspect of thepresent invention, the air feed start timing to the nozzle is set sothat the nozzle is brought thereinside to the atmospheric pressure statein a time after the nozzle reaches the lowest fall point before thenozzle starts to rise, thereby releasing the suction and mounting theelectronic component on the circuit board. Thus the time required forreturning the vacuum pressure in the air passage to atmospheric pressurecan be shortened in comparison with the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention willbecome clear from the following description taken in conjunction withthe preferred embodiments thereof with reference to the accompanyingdrawings, in which:

FIG. 1 is a diagram showing a component holding apparatus according to afirst embodiment of the present invention;

FIG. 2 is a flow chart of the operation of the component holdingapparatus of FIG. 1;

FIG. 3 is a timing chart of the operation related to the componentholding apparatus shown in FIG. 1;

FIG. 4 is a perspective view of a component mounting apparatus havingthe component holding apparatus of FIG. 1;

FIG. 5 is a diagram showing a component holding apparatus according to asecond embodiment of the present invention;

FIG. 6 is a sectional view of a first packing shown in FIG. 5;

FIG. 7 is a diagram of a component holding apparatus according to athird embodiment of the present invention;

FIG. 8 is a sectional view of a second packing shown in FIG. 7;

FIG. 9 is a sectional view of a state wherein the first packing of FIG.5 deviates in a direction about an axis of a spline shaft from thespline shaft as a result of rotation of the spline shaft in thedirection;

FIG. 10 is a sectional diagram of a press-type packing installed in acomponent holding apparatus according to a fourth embodiment of thepresent invention;

FIG. 11 is a sectional diagram of the spline shaft specifically showinga groove formed in an axial direction of the spline shaft;

FIG. 12 is a perspective view of a base member of the press-type packingof FIG. 10;

FIG. 13 is a perspective view of a modified example of the base member;

FIG. 14 is a diagram showing the structure of a conventional componentholding apparatus;

FIG. 15 is a flow chart of the operation of the component holdingapparatus of FIG. 14; and

FIG. 16 is a timing chart of the operation related to the componentholding apparatus of FIG. 14.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An apparatus for holding components, an apparatus for mountingcomponents which comprises the component holding apparatus, and acomponent mount method carried out by the component mounting apparatusaccording to preferred embodiments of the present invention will bedescribed below with reference to the drawings. Like parts aredesignated by like reference numerals throughout the drawings includingFIGS. 14 and 15 used in the foregoing description, and the descriptionof the like parts will be omitted here. A part performing the functionof the “component holding apparatus” in the above SUMMARY OF THEINVENTION corresponds to a part having a component sucking head part206, a suction device 103, a first blow device 106 and a second blowdevice 217, and moreover corresponds to a part with a sealing member 351or 451 or 502 added to the above parts. An electronic component isexemplified as the “component” in the embodiments.

First Embodiment

FIG. 4 schematically shows the whole of a component mounting apparatus250 according to a first embodiment of the present invention. 202 is atransfer part for carrying in and out an electronic circuit board 201and, holding the circuit board 201 during a production process. 203 and204 are electronic component feed parts for storing and feedingelectronic components to be mounted to the circuit board 201. Theelectronic component feed part 203 is a reel-type feed part in which atape having electronic components temporarily fixed thereto is wound ina reel, and the electronic component feed part 204 is a tray-type feedpart in which electronic components are stored in a tray. A componentsucking head part 206 having a nozzle 208 for sucking of electroniccomponents moves up and down, rotates, etc. the nozzle 208, which isconnected to an X-Y robot 205 which moves the head part 206 in X, Ydirections. When the electronic component is to be sucked, the componentsucking head part 206, i.e., nozzle 208 is moved by the X-Y robot 205 toan electronic component hold position at the electronic component feedpart 203 or 204, where the component sucking head part 206 lowers thenozzle 208 to suck the electronic component and then raises the nozzle208 after sucking the electronic component. A suction state of theelectronic component sucked by the nozzle 208 is picked up by acomponent recognition camera 207. Whether it is necessary to correct asuction angle of the electronic component, etc. is checked on the basisof information of the picked-up image before the electronic component ismounted to the electronic circuit board 201. The electronic componentsucked by the nozzle 208 is moved in X, Y directions through movement ofthe head part 206 by the X-Y robot 205 to a predetermined position onthe electronic circuit board 201. The nozzle 208 is moved down by theoperation of the head part 206, mounts the electronic component to apredetermined component mount position on the electronic circuit board201, and releases the suction to the electronic component. Eachelectronic component is mounted onto the electronic circuit board 201from the electronic component feed part 203 or 204 in repeated sequencesof the above operations.

FIG. 1 shows the component sucking head part 206 including theabove-described nozzle 208, the above X-Y 18 robot 205, a suction device103 for sucking the electronic component by the nozzle 208, a first blowdevice 106, a second blow device 217, and a control device 211controlling operations of the component sucking head part 206, X-Y robot205, suction device 103, first blow device 106 and second blow device217. A part working the function of the “component holding apparatus”corresponds, as described before, to a part with the component suckinghead part 206, suction device 103, first blow device 106, and secondblow device 217. Although it is so indicated in FIG. 1 for the sake ofconvenience that the X-Y robot 205 directly drives a spline shaft 213having the nozzle 208, the component sucking head part 206 is moved bythe X-Y robot 205 as depicted hereinabove.

As will be discussed in detail later, according to the presentembodiment in contrast to the prior art, the spline shaft 213 isprovided with a voice coil motor 221 for axially moving the spline shaft213 having the nozzle 208 set at one end part 213 a thereof, and also adetection device for detecting a movement amount of the spline shaft 213in the axial direction. Parts similar to those of the conventional headpart 101 are described roughly here.

Two nuts 131, 134 are fitted to the spline shaft 213 along an axialdirection of the spline shaft 213 to let the spline shaft 213 slide inthe axial direction. These nuts 131, 134 are supported by a body part(not shown) of the component sucking head part 206 via respectivebearings 132, 133. Accordingly, the spline shaft 213 is rendered movablein the axial direction relative to the body part and rotatable in adirection about an axis of the spline shaft 213. The rotation of thespline shaft 213 about the axis is carried out by a motor 142 located atthe component sucking head part 206 via a belt 140. The motor 142 isconnected to the control device 211. A rotation angle of the splineshaft 213 about the axis is calculated by the control device 211, forinstance, on the basis of a signal sent from an encoder fitted to themotor 142. The operation of the motor 142 is feedback controlled on thebasis of the calculation result, so that the rotation angle iscontrolled.

The nozzle 208 for sucking of the electronic component 138 is located atone end part 213 a of the spline shaft 213. The nozzle has a filter 137installed to prevent invasion of dust at the suction time. An airpassage 227 for air sucked via the filter 137 and blow air is formedinside the spline shaft 213 along the axial direction from one end part213 a of the spline shaft 213 through the interior of the voice coilmotor 221 (described later) to the other end part 213 b of the splineshaft 213. Similar to the prior art device, the air passage 227 isconnected with a suction tube 105 communicating with the suction device103 at the other end part 213 b of the spline shaft 213. The suctiondevice 103 is connected to the control device 211 and controlled inoperation by the control device 211. The suction operation of thesuction device 103 sucks air from a leading end of the nozzle 208through the air passage 227 and filter 137, thereby the electroniccomponent 138 is sucked at the leading end part of the nozzle 208.Further, the first blow device 106 branching from the suction tube 105is connected at the other end part 213 b of the spline shaft 213. Thefirst blow device 106 is also connected to the control device 211.

At a part of the spline shaft 213, which is held between the bearings132 and 133 supporting the spline shaft 213 rotatably to the body partof the component suction head part 206, there is arranged the voice coilmotor 221 using the spline shaft 213 as a driving shaft. A magnet 223 isfixed to a circumferential face of the spline shaft 213. A voice coil222 is installed in a casing 221 a of the can-shaped voice coil motor221 extending in the axial direction of the spline shaft 213, morespecifically, in the periphery of the magnet 223 in the axial directionof the spline shaft 213 within a movement range of the spline shaft 213in the axial direction. The voice coil 222 is held in a state in whichthere is no contact with the magnet 223. The thus-arranged voice coilmotor 221 is connected to the control device 211 of the componentmounting apparatus and controlled in operation by the control device211. That is, when power is fed to the voice coil 222, the magnet 223 ofthe voice coil motor 221 moves between a rise position 212 a and a fallposition 212 b, thereby moving the spline shaft 213 and nozzle 208 inthe axial direction. The voice coil motor 221 can be constructed inanother structure wherein the voice coil is fixed to the circumferentialface of the spline shaft 213 and the magnet is provided in the peripheryof the voice coil in a state not in contact with the voice coil alongthe axial direction of the spline shaft 213 within the movement range ofthe spline shaft 213.

An opening is formed in the vicinity of the one end part 213 a of thespline shaft 213 for connecting the air passage 227 with the second blowdevice 217. In the embodiment, a shaft opening 227 a is formed in theair passage 227 in an internal part 224 of the voice coil motor 221 in adiametrical direction of the spline shaft 213. Moreover, a hole 226 isopened in the casing 221 a of the voice coil motor 221. An air joint 225fitted at a part where the hole 226 is opened at a surface of the casing221 a is connected to the second blow device 217 of the componentmounting apparatus via a hose, which is comprised in the componentsucking head part 206 or the component mounting apparatus. Both theshaft opening 227 a and the hole 226 are opened to the internal part 224of the voice coil motor 221. The first blow device 106 and the secondblow device 217 work to feed compressed air consequent to themanipulation of valves into the air passage 227 in order to return avacuum pressure in the air passage 227 generated by the suction device103 to a state of atmospheric pressure. The first and second blowdevices 106 and 217 are controlled in operation by the control device211. The second blow device 217 feeds air in approximately eight timesthe amount supplied by the first blow device 106 according to thepresent embodiment. While the vacuum pressure in the air passage 227 isreturned to the atmospheric pressure because of the blow operation ofthe first and second blow devices 106, 217, the air passage 227 can bereturned to atmospheric pressure in a shorter time than in the prior artdue to the addition of the second blow device 217 in the vicinity of thenozzle 208.

Meanwhile, a rod-like magnetic scale 228 is set in the axial directioncoaxially with the spline shaft 213 at the other end part 213 b of thespline shaft 213. The magnetic scale 228 corresponds to an embodimentfunctioning as a member to be detected. S and N poles are alternatelymagnetized via a constant interval in the axial direction of themagnetic scale 228. The magnetic scale 228 is arranged coaxially withthe spline shaft 213 so as to prevent the magnetic scale 228 fromrotating circlewise in consequence to the rotation of the spline shaft213 about the axis by the motor 142, thereby facilitating magneticdetection by a magnetic sensor 229 to be described later.

In order to detect magnetism of the magnetic scale 228, the magneticsensor 229 is fixed to the component sucking head part 206 in a state inwhich the sensor does not contact the magnetic scale 228. A change inmagnetism due to an axial movement of the magnetic scale 228 subsequentto the axial movement of the spline shaft 213 is detected by themagnetic sensor 229 and, detected information is sent to the controldevice 211 from the magnetic sensor 229. A transmission sensor 230 isfixed to the component sucking head part 206 at a leading end part ofthe magnetic scale 228 in a state in which the transmission sensor doesnot touch the magnetic scale 228 to detect a movement origin of thespline shaft 213. The transmission sensor 230 has, e.g., alight-emitting element and a photodetecting element, detecting whetheror not the light is shut by the leading end of the magnetic scale 228. Adetection result is sent to the control device 211. The above-describedmagnetic scale 228, magnetic sensor 229 and transmission sensor 230correspond to an embodiment performing the function of the detectiondevice.

Based on the detection result supplied from the transmission sensor 230,the control device 211 judges a time point, for instance, when theabsence of shutting changes to the presence of the shutting as theorigin. Moreover, the control device 211 calculates a movement amount ofthe spline shaft 213 based on information of a change of magnetic polesmagnetized to the magnetic scale 228 which is supplied from the magneticsensor 229, and controls the power supply to the voice coil motor 221based on the above calculation result, thereby controlling the operationof the voice coil motor 221.

The detection device for detecting the movement amount of the splineshaft 213 is not limited to the above-described magnetic scale 228,magnetic sensor 229 and transmission sensor 230. Any known instrumentcapable of measuring the movement amount of the spline shaft 213 isusable as the detection device.

The operation of the component mounting apparatus having the componentholding apparatus including the component sucking head part 206 of theembodiment constructed as above will be described with reference to FIG.2.

Under the control of the control device 211, the transfer part 202carries in the electronic circuit board 201 from a previous process andit is supported at a mount position. On the other hand, the transmissionsensor 230 of the component sucking head part 206 detects the movementorigin of the spline shaft 213 when the light is shut by the leading endof the magnetic scale 228. Detected information of the origin is sentfrom the transmission sensor 230 to the control device 211.

At step 1, the X-Y robot 205 moves the component sucking head part 206to the component hold position at the reel-type feed part 203 or thetray-type feed part 204 through control of the control device 211.

At step 2, under the control by the control device 211, the voice coilmotor 221 is turned conductive and thus the spline shaft 213 is moveddown. At this time, the control device 211 controls a descent amount ofthe spline shaft 213 on the basis of information output from themagnetic sensor 229 consequent to the descent of the magnetic scale 228.When the spline shaft 213 and nozzle 208 are moved down by driving ofthe voice coil motor 221, at step 3, the suction device 103 starts thesuction operation under the control of the control device 211. The airis sucked from the leading end of the nozzle 208 through the air passage227 and filter 137. At step 4, when the leading end of the nozzle 208comes close to or touches the electronic component 138 stored in thereel-type feed part 203 or the tray-type feed part 204, the electroniccomponent 138 is sucked to the leading end of the nozzle 208.

At step 5, under the control of the control device 211, the voice coilmotor 221 is moved after the electronic component 138 is sucked, therebythe nozzle 208 is moved up until the magnet 223 of the voice coil motor221 reaches the rise position 212 a. The control device 211 thencontrols the X-Y robot 205 to move the component sucking head part 206to a position above the component recognition camera 207. The componentrecognition camera 207 picks up an image of an attitude of theelectronic component 138 sucked by the nozzle 208, and sends informationof the picked-up image to the control device 211. If necessary, thecontrol device 211 drives the motor 142 on the basis of the imageinformation thereby rotating the spline shaft 213 via the belt 140 aboutthe axis of the spline shaft 213. The attitude of the sucked electroniccomponent is thus adjusted.

At step 6, under the control of the control device 211, the X-Y robot205 moves the component sucking head part 206 to a position above theelectronic circuit board 201. The control device 211 again supplieselectricity to the voice coil motor 221 at step 7, thereby lowering thespline shaft 213 and nozzle 208. While lowering as above, the controldevice 211 drives the first blow device 106 and second blow device 217at step 8 to supply air into the air passage 227. As a result, thevacuum pressure in the air passage 227 is returned to atmosphericpressure.

According to the present embodiment, although the first and second blowdevices 106, 217 start to operate simultaneously, the second blow device217 may be adapted to start earlier because the second blow device 217has a larger air feed capacity than that of the first blow device 106.FIG. 3 indicates a timing at which the interior of the air passage 227is returned to atmospheric pressure immediately before the nozzle 208starts to move upward. An operation start timing of the first and secondblow devices 106, 217 is set so that the interior of the air passage 227is returned to atmospheric pressure within a period (corresponding toXIV in the drawing) from a time of the nozzle 208 reaching a lowest fallpoint when the magnet 223 of the voice coil motor 221 reaches the fallposition 212 b to a time of the nozzle 208 starting to move upward. Inthe present embodiment, the operation start timing is set at 40 msecearlier than the nozzle 208 reaches the lowest fall point. An operationtime (corresponding to XI of FIG. 3) of the first and second blowdevices 106, 217 is approximately 60 msec in the embodiment. Anoperation termination time of the first and second blow devices 106, 217coincides with a time when the nozzle 208 starts to move upward.

The operation time of the first and second blow devices 106, 217 is setin the control device 211 beforehand by a timer in conformity with,e.g., a size of the component held by the nozzle 208.

For instance, when the component held by the nozzle 208 is a QFP (QuadFlat Gull Wing Leaded Package) component of a weight exceedingapproximately 5 g, or an irregular shape component of a weight exceedinga weight slightly lighter than 5 g such as the QFP of a size ofapproximately 40×40 mm, or the irregular shape component of a connectorand the like, the operation time of the first and second blow devices106, 217 is set to a time shorter than the aforementioned about 60 msecsuch that the first and second blow devices 106, 217 start to operatewhen the nozzle 208 reaches the lowest fall point and finish when thenozzle 208 starts to move upward. The reason for this is that since alarge component having the above weight is heavier than a normalcomponent, a suction force would decrease if the blow operation werestarted before the nozzle 208 reaches the lowest fall point and, theheld component were dropped before landing on the circuit board 201.That the held component lands on the circuit board 201 is detectablebased on the movement amount of the spline shaft 213 based on theinformation sent from the magnetic sensor 229 and a change of a loadacting on the voice coil motor 221, i.e., a change of current suppliedto the voice coil motor 221. The control device 211 stores beforehandinformation of a mount order of components to the circuit board 201,information related to components to be mounted in accordance with themount order information and information of a mount position ofcomponents at the circuit board 201, etc. Since the above informationrelated to components includes information of sizes, weights, etc. ofthe components, the control device 211 recognizes the weight of thecomponent being held by the nozzle 208 and can select the operation timecorresponding to the component among the operation times of the firstand second blow devices 106, 217 set by the timer as above.

When the interior of the air passage 227 is returned to the atmosphericpressure, the sucked electronic component 138 is mounted to thecomponent mount position to the component mount position on the circuitboard 201. At step 9, the nozzle 208 moves up after the mounting, andprepares for suction of a next component.

As described hereinabove, according to the component holding apparatusof the embodiment, and the component mounting apparatus having thecomponent holding apparatus, the first and second two blow devices 106and 217 are provided, and moreover, the second blow device 217 is set toperform the blow action from the vicinity of the nozzle 208. Therefore,the time required for returning the interior of the air passage 227 tothe atmospheric pressure from the vacuum pressure is shortened incomparison with the prior art. A component mount time XV of FIG. 3 isshortened than the conventional time V. The component mount time XV is aperiod corresponding to the movement of the head part, that is, from atime when the nozzle 208 starts to fall and then sucks the component toa time of when the nozzle 208 finishes moving upward.

In the present embodiment, the spline shaft 213 is moved by the voicecoil motor 221 on the spline shaft 213 and the power supply to the voicecoil motor 221 is controlled by the control device 211. The spline shaft213 is accordingly moved correctly. A pressure applied to the electroniccomponent 138 from the nozzle 208 when the nozzle 208 sucks theelectronic component 138 and when the nozzle mounts the suckedelectronic component 138 to the circuit board 201 can be controlled bycontrolling the power to the voice coil motor 221.

The magnetic scale 228, detecting the movement of the spline shaft 213,is directly coupled to the spline shaft which is a rigid body, and alsothe nozzle 208 is directly coupled to the rigid spline shaft 213.Therefore, the movement amount of the magnetic scale 228 because of theaxial movement of the spline shaft 213 perfectly agrees with themovement amount of the nozzle 208 in the axial direction. With theadoption of this structure, the movement amount of the spline shaft 213when the spline shaft 213 is lowered to let the leading end of thenozzle 208 touch the electronic component 138 and when the electroniccomponent sucked by the nozzle 208 is mounted on the electronic circuitboard 201 can be correctly detected by detecting the movement amount ofthe magnetic scale 228.

The mounting quality of the electronic component is improved accordingto the present embodiment.

Though the spline shaft 213 with the nozzle 208 moves vertically in theembodiment, the movement direction of the spline shaft 213 is notrestricted to this and can be set in accordance with a direction of thecomponent feed part and the circuit board.

Although the electronic component is described as an example of thecomponent in the embodiment, the present invention is not limited tothis. Likewise, although the electronic circuit board embodiment as anobject to which the component is mounted, the present invention is notlimited to the electronic circuit board.

Second Embodiment

As shown in FIG. 1 and described hereinabove, in the component holdingapparatus having the component sucking head part 206 of the firstembodiment, the suction of the electronic component 138 by the nozzle208 is executed by the suction device 303 from the other end part 213 bof the spline shaft 213 through the air passage 227 extending in theaxial direction inside the spline shaft 213. A component holdingapparatus may be constructed, which comprises a component sucking headpart 306 which is a modification of the component sucking head part 206,as shown in FIG. 5. A structure of the component holding apparatus withthe component sucking head part 306 is equal to that of theabove-described component holding apparatus having the component suckinghead part 206 except the following point. According to the componentholding apparatus including the component sucking head part 306, an airpassage 327 in a spline shaft 313 is formed to run only slightly beyondthe shaft opening 227 a from one end part 313 a toward the other endpart 313 b, so that air in the air passage 327 is sucked by the suctiondevice 303 through the shaft opening 227 a constituting a part of theair passage 327, the internal part 224 of a voice coil motor 321, a hole326 opened in a casing 321 a of the voice coil motor 321 and the suctiontube 105. The air joint 225 is set at a part where the hole 326 isopened at a surface of the casing 321 a. A first blow device 316branching from the suction tube 105 is connected to the suction tube105. Structurally, in the component holding apparatus having thecomponent sucking head part 306, the first blow device 316 cannot bearranged in the vicinity of the voice coil motor 321, and therefore thefirst blow device 316 is connected to the voice coil motor 321 via apiping of a length approximately eight times that of the second blowdevice 217 disposed in the vicinity of the voice coil motor 321. Assuch, the interior of the air passage 327 cannot be promptly returned tothe atmospheric pressure by the first blow device 316 alone in thecomponent holding apparatus with the component sucking head part 306,similar to the earlier-described first embodiment.

An inconvenience as follows is brought about in the case where the airin the air passage 327 is sucked via the internal part 224 of the voicecoil motor 321 as in the component holding apparatus having thecomponent sucking head part 306. While two nuts 131, 134 are fitted tothe spline shaft 213 to make the spline shaft 213 slidable in the axialdirection as discussed before, the nuts 131, 134 allow the spline shaft213 to slide in the axial direction through an engagement of balls 151of the nuts 131, 134 in grooves 251 formed in a circumferential facealong the axial direction of the spline shaft 213. FIG. 11 shows asectional view of the spline shaft 213, specifically positions where thegrooves 251 are formed in the direction about the axis of the splineshaft 213. The grooves 251 are similarly formed also in the spline shaft313 of the component sucking head part 306 of the second embodiment.

Since the grooves 251 are formed nearly all over the length of thespline shaft 313 penetrating the voice coil motor 321 as shown in FIG.5, and in the structure whereby the air in the voice coil motor 321 issucked by the suction device 303, at a part of the spline shaft 313where the spline shaft 313 penetrates the casing 321 a of the voice coilmotor 321, the circumferential face including the above grooves 251should be sealed to avoid the leakage of air. What is difficult in thissealing is to secure air-tightness at the part of the grooves 251because the spline shaft 313 not only moves in the axial direction, butrotates about the axis as discussed before.

In the first embodiment, although the interior 224 of the voice coilmotor 221 and the air passage 227 communicate with each other via theshaft opening 227 a, the suction device 103 is connected to the airpassage 227 and the air in the air passage 227 is sucked mainly by thesuction device 103. Therefore the aforementioned tightness does notmatter. Moreover, since the blow operation by the second blow device 217less induces tightness than the suction operation, sealing tightness canbe disregarded in the

First Embodiment.

In order to solve the above problem, according to the component holdingapparatus having the component sucking head part 306 in the secondembodiment, a first packing 351 is provided as a sealing member at thepart where the spline shaft 313 penetrates the casing 321 a, which isheld to the casing 321 a by a lid 352. The first packing 351 is, as isshown in FIG. 6, in the same sectional shape as the spline shaft 313,with having a hole through which the spline shaft 313 b penetrates. Thepacking is formed of highly flexible material, and pressed to the casing321 a by the lid 352 into tight contact with an outer face of the casing321 a and the circumferential face of the spline shaft 313. According tothe present embodiment, urethane rubber is used for the first packing351. Because of the employment of the first packing 351 as above, theinterior 224 of the voice coil motor 321 is tightly sealed, thuspreventing a degree of vacuum of the interior 224 of the voice coilmotor 321 from being decreased as a result of the leakage of air to theinterior 224 of the voice coil motor 321 through the circumferentialface of the spline shaft 313 including the grooves 251 consequent to thesuction operation by the suction device 303. Sufficient suctionoperation by the nozzle 208 is ensured accordingly.

Third Embodiment

The component holding apparatus having the component sucking head part306 of the second embodiment can be formed in a modified constitution asshown in FIG. 7. As described above, the first packing 351 uses softmaterial of urethane rubber or the like to enhance coherence to thespline shaft 313 and is kept in perfect contact with the spline shaft313 in section. However, in the structure where the first packing 351 isheld between the casing 321 a and lid 352 to be directly in touch withthe casing 321 a and lid 352, the grooves 251 formed in the spline shaft313 and projecting parts 353 formed in the first packing 351 to beengaged with the grooves 251 deviate from each other in a rotationaldirection due to the flexibility of the packing 351 when the splineshaft 313 rotates about the axis, as shown in FIG. 9, which possiblyresults in the leak of air through the grooves 251.

Therefore, in the component holding apparatus having a component suckinghead part 406 of FIG. 7, a sandwich-type packing 451 is used as thesealing member in place of the first packing 351. The sandwich-typepacking 451 comprises a soft first packing 452 which has a hole of thesame sectional shape as the spline shaft 313 and comes in tight contactwith the spline shaft 313 as well as the first packing 351, and a pairof second packings 454 of higher rigidity than the first packing 452.The second packing 454 has projecting parts 453 which are meshed in thegrooves 251 of the spline shaft 313, thereby rotating the second packing454 to follow the rotation of the spline shaft 313 about the axis, thuseliminating a relative displacement to the spline shaft 313. The firstpacking 452 is sandwiched between the second packings 454. Thesandwich-type packing 451 is pressed by the lid 352 to the casing 321 aand thus set with the second packings 454 kept in touch with the casing321 a and lid 352.

In the component holding apparatus having the component sucking headpart 406, the first packing 451 is formed of urethane rubber, similar tothe packing 351. The second packing 454 is formed of DURACON (trademarkof duPont Co.) of 100-1000 times a rigidity of urethane rubber. Sincethe second packing 454 has high rigidity, the second packing 454 canrotate integrally with the spline shaft 313 simply when the projectingparts 453 are engaged in the grooves 251. The projecting parts 453 ofthe second packing 454 may be formed with the utilization of a drillingtreatment, so that process costs are reduced. If it is so designed at adrilling process of the drilling treatment as to reduce a contact partbetween the circumferential face of the spline shaft 313 and the secondpacking 454, a frictional resistance of the spline shaft 313 and secondpacking 454 is lessened and a long life is secured for the secondpacking 454. A slight amount of grease or the like is applied to thecontact part between the sandwich-type packing 451 and the spline shaft313, casing 321 a and lid 352 to enhance vacuum sealing properties.

When the spline shaft 313 rotates about the axis, the second packings454 constituting the above-formed sandwich-type packing 451 integrallyrotate with the spline shaft 313 in coincident with the rotation of thespline shaft 313 in a state to be in touch with the casing 321 a and lid352. Since the first packing 452 rotates synchronously with the secondpackings 454, the spline shaft 313 and the first packing 452 neverdeviate from each other in the rotational direction, whereby the degreeof vacuum in the internal part 224 of the voice coil motor 321 isprevented from decreasing and sufficient suction operation by the nozzle208 is secured.

Fourth Embodiment

The sandwich-type packing 451 in the above third embodiment can bemodified in a constitution shown in FIG. 10. The first blow device 316and second blow device 217 inject air to the internal part 224 of thevoice coil motor 321. The injected air is apt to flow outside throughthe internal part 224 of the voice coil motor 321 through the grooves251 of the spline shaft 313 at the part where the spline shaft 313penetrates the casing 321 a. At this time, in FIG. 10, the injected airsometimes leaks outside through a part of a contact face 501 between thesecond packing 454 of the sandwich-type packing 451 and the casing 321 aof the voice coil motor 321. Once the air leaks through the contact facepart 501, an air passage is formed at the contact face part 501. So, itis conceivable that a disadvantage hindering the suction operation bythe suction device 303 may be arised.

In the fourth embodiment, a press-type packing 502 shown in FIG. 10 isprovided as the sealing member at the part where the spline shaft 313penetrates the casing 321 a of the voice coil motor 321. The press-typepacking 502 comprises a third packing 503, a packing 504 at the side ofthe motor in touch with the casing 321 a of the voice coil motor 321, apacking 505 at the side of the lid in touch with the lid 352, and apressing member constructed by a base member 506 and an urging member507.

Similar to the above-described first packings 351, 452, the thirdpacking 503 has a hole of the same sectional shape as the spline shaft313, is soft in tight contact with the spline shaft 313 and formed ofurethane rubber.

The packing 504 at the side of the motor and packing 505 at the side ofthe lid correspond to the above second packings 454. A pair of packingis formed by the packings 504, 505. Each of the packings 504, 505 ofhigh rigidity has projecting parts 453 which are engaged with thegrooves 251 of the spline shaft 313 thereby rotating the packings 504,505 in accordance with the rotation of the spline shaft 313 about theaxis of the spline shaft 313 to eliminate the relative displacement inthe rotational direction to the spline shaft 313. The packings 504, 505are formed of DURACON (trademark of duPont Co.), similar to the secondpackings 454. The third packing 503 is interposed between the packings504 and 505.

As shown in FIG. 12, the base member 506 includes a recessed part 508having an opening 512 in which the third packing 503 is fitted andthrough which the spline shaft 313 penetrates, and a flange part 509provided at the recessed part 508 to which the urging member 507 isbrought into contact. Projecting parts 510 are formed at the opening 512of the recessed part 508, which are engaged with the grooves 251 of thespline shaft 313 similar to the projecting parts 453, thereby preventingthe relative displacement in the rotational direction of the base member506 to the rotation of the spline shaft 313.

The urging member 507 is set between the third packing 503 and packing504 at the side of the motor, that is, in the embodiment between theflange part 509 and the packing 504 at the side of the motor, pressingthe packing 504 to the casing 321 a of the voice coil motor 321 with aforce of 30-40 g. Although a spring is used as the urging member 507 inthe embodiment, anything that generates the above urging force isutilizable and the urging member is not limited to the spring.

In the presence of the press-type packing 502 constituted as above,similar to the sandwich-type packing 451, the packing 504 at the side ofthe motor and the packing 505 at the side of the lid rotate integrallywith the spline shaft 313 in coincident with the rotation thereof whilekeeping touch with the casing 321 a and lid 352 when the spline shaft313 rotates about the axis. Thus, since the third packing 503 rotatessynchronously with the packings 504 and 505, the spline shaft 313 andthe third packing 503 never deviate from each other in the rotationaldirection, thereby avoiding a decrease of the degree of vacuum in theinterior 224 of the voice coil motor 321. So, sufficient suctionoperation by the nozzle 208 is hence ensured. In addition, even if theair passage is defined, through which the air injected by the blowoperation to leak outside between the contact face part 501 of thecasing 321 a of the voice coil motor 321 and the packing 504 at the sideof the motor, since the packing 504 of the press-type packing 502 ispressed to the casing 321 a of the voice coil motor 321 by the urgingmember 507, the air passage formed at the contact face part 501 isbroken and shut when the blow operation is finished. The suctionoperation is accordingly never obstructed.

Although the recessed part 508 is formed at the base member 506 of theabove press-type packing 502, the base member 506 is not limited in theabove form. In other words, the recessed part 508 acts to prevent apositional displacement of the base member 506 to the third packing 503and therefore is not required to be recessed so long as it exerts theaction. For instance, a constitution as a base member 511 as shown inFIG. 13 may be formed, which has a member 513 for prevention of thepositional displacement projected on a circular plate materialfunctioning as the opening 512 and the flange part 509.

Although the present invention has been fully described in connectionwith the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims unless they departtherefrom.

1. An apparatus for holding a component, comprising: a shaft having anozzle at one end of said shaft, said shaft being movable in an axialdirection of said shaft and rotatable about an axis of said shaft; avoice coil motor extending in said axial direction of said shaft, saidvoice coil motor including (i) a casing through which said shaftextends, (ii) one of a magnet and a coil fixed to a circumferential faceof said shaft, and (iii) the other of said magnet and said coilpositioned within said casing and surrounding said one of said magnetand said coil, with said shaft being movable in said axial direction viaaction of said magnet and said coil, and with said shaft having an airpassage connecting said nozzle with an interior of said casing; asuction device connected to said voice coil motor and communicating withsaid air passage and said nozzle such that when said suction device isactivated air is sucked from the interior of said casing and said airpassage so as to cause said nozzle to suck and hold a component; a firstblow device connected to said voice coil motor such that when said firstblow device is activated air is supplied into the interior of saidcasing and into said air passage for returning the interior of saidcasing and said air passage to an atmospheric state so as to release thecomponent from said nozzle; a second blow device connected to said voicecoil motor such that when said second blow device is activated air issupplied into the interior of said casing and into said air passage forreturning the interior of said casing and said air passage to anatmospheric state, faster than said first blow device is to return theinterior of said casing and said air passage to an atmospheric state, soas to release the component from said nozzle; and a sealing memberincluding a first packing, at a part of said casing where said shaftpasses through said casing, for preventing passage of air into theinterior of said casing while said suction device is activated, saidfirst packing having (i) a sectional shape that is the same as asectional shape of said shaft, and (ii) a hole through which said shaftextends.
 2. The apparatus according to claim 1, further comprising: agroove, extending in said axial direction, in said circumferential faceof said shaft, wherein said sealing member further includes two secondpackings between which is sandwiched said first packing, said two secondpackings being of a material having a rigidity greater than a rigidityof a material of said first packing, said two second packings eachhaving a hole through which said shaft extends, and said two secondpackings also each having a projection extending into said groove suchthat said two second packings are rotatable with said shaft without anyrelative displacement between said shaft and said two second packings.3. The apparatus according to claim 2, wherein one of said two secondpackings is in contact with said casing, and said sealing member furtherincludes an urging member between said first packing and said one ofsaid two second packings, such that said urging member urges said one ofsaid two second packings against said casing with a force sufficient toeliminate air pressure generated at an interface of said casing and saidone of said two second packings when the interior of said casing isreturned to the atmospheric state by either said first blow device orsaid second blow device, so as to prevent leakage of air duringactivation of said suction device.
 4. The apparatus according to claim3, further comprising: a control device connected to said first blowdevice and said second blow device, said control device for controllingan air feed start time of said first blow device and said second blowdevice such that said air passage is returned to the atmospheric stateduring a period from when said nozzle holds a component and reaches alowest fall point to a time when said nozzle starts to rise so as tohave the component released from said nozzle and mounted onto an object.5. The apparatus according to claim 4, wherein said control device isfor controlling the air feed start time based on a weight of thecomponent held by said nozzle such that if the weight of the componentheld by said nozzle exceeds approximately 5 g the air feed start time isa point in time when said nozzle reaches the lowest fall point.
 6. Theapparatus according to claim 2, further comprising: a control deviceconnected to said first blow device and said second blow device, saidcontrol device for controlling an air feed start time of said first blowdevice and said second blow device such that said air passage isreturned to the atmospheric state during a period from when said nozzleholds a component and reaches a lowest fall point to a time when saidnozzle starts to rise so as to have the component released from saidnozzle and mounted onto an object.
 7. The apparatus according to claim6, wherein said control device is for controlling the air feed starttime based on a weight of the component held by said nozzle such that ifthe weight of the component held by said nozzle exceeds approximately 5g the air feed start time is a point in time when said nozzle reachesthe lowest fall point.
 8. The apparatus according to claim 1, furthercomprising: a control device connected to said first blow device andsaid second blow device, said control device for controlling an air feedstart time of said first blow device and said second blow device suchthat said air passage is returned to the atmospheric state during aperiod from when said nozzle holds a component and reaches a lowest fallpoint to a time when said nozzle starts to rise so as to have thecomponent released from said nozzle and mounted onto an object.
 9. Theapparatus according to claim 8, wherein said control device is forcontrolling the air feed start time based on a weight of the componentheld by said nozzle such that if the weight of the component held bysaid nozzle exceeds approximately 5 g the air feed start time is a pointin time when said nozzle reaches the lowest fall point.
 10. An apparatusfor mounting a component, comprising: a shaft having a nozzle at one endof said shaft, said shaft being movable in an axial direction of saidshaft and rotatable about an axis of said shaft; a voice coil motorextending in said axial direction of said shaft, said voice coil motorincluding (i) a casing through which said shaft extends, (ii) one of amagnet and a coil fixed to a circumferential face of said shaft, and(iii) the other of said magnet and said coil positioned within saidcasing and surrounding said one of said magnet and said coil, with saidshaft being movable in said axial direction via action of said magnetand said coil, and with said shaft having an air passage connecting saidnozzle with an interior of said casing; a suction device connected tosaid voice coil motor and communicating with said air passage and saidnozzle such that when said suction device is activated air is suckedfrom the interior of said casing and said air passage so as to causesaid nozzle to suck and hold a component; a first blow device connectedto said voice coil motor such that when said first blow device isactivated air is supplied into the interior of said casing and into saidair passage for returning the interior of said casing and said airpassage to an atmospheric state so as to release the component from saidnozzle; a second blow device connected to said voice coil motor suchthat when said second blow device is activated air is supplied into theinterior of said casing and into said air passage for returning theinterior of said casing and said air passage to an atmospheric state,faster than said first blow device is to return the interior of saidcasing and said air passage to an atmospheric state, so as to releasethe component from said nozzle; and a sealing member including a firstpacking, at a part of said casing where said shaft passes through saidcasing, for preventing passage of air into the interior of said casingwhile said suction device is activated, said first packing having (i) asectional shape that is the same as a sectional shape of said shaft, and(ii) a hole through which said shaft extends.
 11. The apparatusaccording to claim 10, further comprising: a groove, extending in saidaxial direction, in said circumferential face of said shaft, whereinsaid sealing member further includes two second packings between whichis sandwiched said first packing, said two second packings being of amaterial having a rigidity greater than a rigidity of a material of saidfirst packing, said two second packings each having a hole through whichsaid shaft extends, and said two second packings also each having aprojection extending into said groove such that said two second packingsare rotatable with said shaft without any relative displacement betweensaid shaft and said two second packings.
 12. The apparatus according toclaim 11, wherein one of said two second packings is in contact withsaid casing, and said sealing member further includes an urging memberbetween said first packing and said one of said two second packings,such that said urging member urges said one of said two second packingsagainst said casing with a force sufficient to eliminate air pressuregenerated at an interface of said casing and said one of said two secondpackings when the interior of said casing is returned to the atmosphericstate by either said first blow device or said second blow device, so asto prevent leakage of air during activation of said suction device. 13.The apparatus according to claim 12, further comprising: a controldevice connected to said first blow device and said second blow device,said control device for controlling an air feed start time of said firstblow device and said second blow device such that said air passage isreturned to the atmospheric state during a period from when said nozzleholds a component and reaches a lowest fall point to a time when saidnozzle starts to rise so as to have the component released from saidnozzle and mounted onto an object.
 14. The apparatus according to claim13, wherein said control device is for controlling the air feed starttime based on a weight of the component held by said nozzle such that ifthe weight of the component held by said nozzle exceeds approximately 5g the air feed start time is a point in time when said nozzle reachesthe lowest fall point.
 15. The apparatus according to claim 11, furthercomprising: a control device connected to said first blow device andsaid second blow device, said control device for controlling an air feedstart time of said first blow device and said second blow device suchthat said air passage is returned to the atmospheric state during aperiod from when said nozzle holds a component and reaches a lowest fallpoint to a time when said nozzle starts to rise so as to have thecomponent released from said nozzle and mounted onto an object.
 16. Theapparatus according to claim 15, wherein said control device is forcontrolling the air feed start time based on a weight of the componentheld by said nozzle such that if the weight of the component held bysaid nozzle exceeds approximately 5 g the air feed start time is a pointin time when said nozzle reaches the lowest fall point.
 17. Theapparatus according to claim 10, further comprising: a control deviceconnected to said first blow device and said second blow device, saidcontrol device for controlling an air feed start time of said first blowdevice and said second blow device such that said air passage isreturned to the atmospheric state during a period from when said nozzleholds a component and reaches a lowest fall point to a time when saidnozzle starts to rise so as to have the component released from saidnozzle and mounted onto an object.
 18. The apparatus according to claim17, wherein said control device is for controlling the air feed starttime based on a weight of the component held by said nozzle such that ifthe weight of the component held by said nozzle exceeds approximately 5g the air feed start time is a point in time when said nozzle reachesthe lowest fall point.